2nd gen pets
Second Generation pets, or "2nd gens" as they are almost always called, are the babies of certain adoptables on the site. Most months, an artist will pick a pair of existing pets, and create a series of potential offspring. They will usually have certain characteristics from both of their parents, and their markings will greatly resemble that of their parents. Since Chicken Smoothie does not (or ever plan to) allow players to "breed" their own pets, this feature serves as a way to celebrate and explore unique combinations of designs.
These litters are released with great frequency, and they can contain pets of any species. They're released to the main monthly adoptables page, under their own tab.
While it is ultimately left to the artists to decide which pairings should created, users are invited to give their input on a forum thread pinned to the top of the CS Help board.
Fortunately 2nd Gen pets are tagged visibly with a stamp that appropriately says "2nd Gen" on it, usually around the site's mark, so it is easy to identify which pets are descendants. This is a trait visible on all stages, even the growing ones.
There are also a section of pets which are called 3rd Generation pets, learn more here!